Postselection is one of the notions that makes quantum computing simultaneously so exciting and perplexing; the idea that for a super-complex problem riddled with variables, you solve by letting the variables take any value at random and postselect for the one combination that makes the problem true. Put another way, rather than solving all the possible combinations to the problem one at a time, you run all possible combinations simultaneously and extract the set of variables that make the problem true.
Quantum mechanics seems to allow for such simultaneous computations of all possible outcomes theoretically, though actually making it happen is another issue altogether (such quantum computing would blow conventional computing methods out of the water). But combined with quantum teleportation - using quantum entanglement to reproduce a quantum state in space that previously existed at another point in space - MIT’s Seth Lloyd and colleagues say you can theoretically teleport a particle back in time.
This form of theoretical time travel solves two major problems associated with the feat. For one, it doesn’t require the bending of spacetime as most time travel theories do. Considering the conditions necessary to bend the fabric of spacetime might only exist in black holes, that’s a good thing. But further, due to the probabilistic laws of quantum mechanics, anything this method of time travel allows to happen already had a finite chance of happening anyhow. That means a particle can’t really go back and accidentally destroy itself.
Of course, the physicists didn’t demonstrate their theory in hopes of going back in time to ensure their parents end up getting married or some such. They’re hoping that by demonstrating these properties they will help push quantum thought toward a theory of gravity. But the idea of moving backward along the timeline without bending the fabric of the universe - or altering ones own future existence - is pretty amazing. If your interest is piqued, you can check out the entire paper here.
Popular Science has been a leading source of science, technology and gadget news since 1872. With up-to-the minute latest space news, insightful commentary on the new innovations and concept cars ...if it's new or future technology you'll find it at popsci.com.au.
WW Media - Popular Science © 2010
Technology - DIY - Videos
Einstein was right about the shortcomings of Quantum Mechanics and so therefore String Theory is also the incorrect approach. As an alternative to Quantum Theory there is a new theory that describes and explains the mysteries of physical reality. While not disrespecting the value of Quantum Mechanics as a tool to explain the role of quanta in our universe. This theory states that there is also a classical explanation for the paradoxes such as EPR and the Wave-Particle
Duality. The Theory is called the Theory of Super Relativity. This theory is a philosophical attempt to reconnect the physical universe to realism and deterministic concepts. It explains the mysterious.